Optical apparatus

ABSTRACT

A projection type display apparatus includes a housing having a first side on which an air intake opening is arranged and a second side on which an air exhaust opening is arranged, a light source for supplying light, and a light valve device which modulates the light output from the light source. A first fan is provided which draws air from the air intake opening into the housing, and a first ventilation path is coupled with the air intake opening so as to lead air flow from the air intake opening toward a lower portion of the light valve. A second ventilation path is formed from the lower portion of the light valve to an upper portion of the light valve, and a second fan is provided which draws out air flowing from the second ventilation path through the air exhaust opening to outside of the housing.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation of U.S. application Ser. No. 11/385,744, filedMar. 22, 2006, which is a continuation of U.S. application Ser. No.11/055,482, filed Feb. 11, 2005, now U.S. Pat. No. 7,021,768, which is acontinuation of U.S. application Ser. No. 10/109,663, filed Apr. 1,2002, now U.S. Pat. No. 6,857,749 which is a continuation of U.S.application Ser. No. 09/911,806, filed Jul. 25, 2001, now U.S. Pat. No.6,431,710, which is a continuation of U.S. application Ser. No.09/347,454, filed Jul. 6, 1999, now U.S. Pat. No. 6,280,038, the subjectmatter of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to optical equipment, such as a liquidcrystal projector. Especially, the invention is concerned with opticalequipment that has a suitable cooling system to cool a light valvearrangement in the optical equipment.

A conventional optical apparatus having a light valve arrangement, asdescribed in Japanese patent Laid-open Publication 8-179424, employs anaxial-flow type ventilation device located under the light valvearrangement as a ventilation system so as to prevent the light valvearrangement from reaching a high temperature. In this case, because theflow of air from the ventilation system can be applied to the lightvalve arrangement directly, the light valve arrangement can be cooled.

Because a ventilation system is provided below the light valvearrangement in the conventional optical equipment, the air is suppliedfrom the base side of the equipment to the ventilation system. Thus, itwas necessary to provide a space on the base side of the equipment toreduce the flow resistance of the air that is drawn in from theequipment side. Further, because the height of the optical equipmentbecomes equal to the height of the ventilation system and a rectifieradded to the height of the projection lens or the light valvearrangement, it was difficult to make the equipment thin.

Further, such space was hard to provide in practical use underneath theprojection lens (dead space) for this ventilation system, so that it wasarranged at a position where it projected from underneath the projectionlens, with a result that it wasn't possible to reduce the size of thewhole device or effect a reduction of the height measurement.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide opticalequipment having a discharge lamp for supplying light, and a light valvedevice for projecting said light, comprising:

a case for housing said optical equipment;

an air intake opening arranged on the side of said case;

a ventilation device adapted to draw in air through said air intakeopening; and

a ventilation path arranged between said ventilation device and saidlight valve device, wherein

said ventilation path is divided into a plurality of air flow paths soas to cool said light valve device by ventilated air from saidventilation device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagrammatic plan view of one of the embodiments of theoptical equipment according to the present invention.

FIG. 2 is a perspective view that shows an example of a ventilationpath.

FIG. 3 is a perspective view that shows an example of cooling structureusing the ventilation path that is illustrated in FIG. 2.

FIG. 4 is a perspective view that shows an embodiment of the opticalequipment according to the present invention.

FIG. 5 is a perspective view that shows another embodiment of theoptical equipment according to the present invention.

FIG. 6 is a sectional view that shows another example of the coolingstructure that is used for optical equipment according to the presentinvention.

FIG. 7 is a sectional view that shows another embodiment of the coolingstructure that is used for optical equipment according to the presentinvention.

FIG. 8 is a diagrammatic plan view of still another embodiment of theoptical equipment according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment of the present invention will be explained withreference to FIG. 1.

In FIG. 1, a light beam 2 from a discharge lamp 1, that is used as alight source, is directed to a polarizing conversion element 6 by meansof a lamp reflector 3 in the form of a parabolic face mirror reflector,through a lens 4 and a lens 5. The light beam 2 is illuminated on afirst dichroic mirror 10 through first lens array 7, mirror 8, andsecond lens array 9.

A red color light component 11 is passed by mirror 10, and light beam12, including a green color light component and a blue color lightcomponent, is reflected by the first dichroic mirror 10. The red colorlight component 11 is reflected by a first mirror 13 onto a first lightvalve 14 through a first polarization plate 81. The green color lightcomponent included in the light beam 12 is reflected by a seconddichroic mirror 15 onto a second light valve 18 through a secondpolarization plate 82. The remaining blue color light component 17included in the light beam 12 passes through the second dichroic mirror15 and is illuminated on a third light valve 21 through a second mirror19, a third mirror 20 and a third polarization plate 83.

A portion of the red light component passing through the first lightvalve 14, a portion of the green light component passing through thesecond light valve 18, and a portion of the blue light component passingthrough the third light valve 21 are combined by a cross dichroic prism25. The combined outgoing light 26 from the cross dichroic prism 25 isprojected on a screen (not shown) by a projection lens 27.

In this embodiment, a color separation optical system is formed by thefirst dichroic mirror 10, the second dichroic mirror 15, the firstmirror 13, the second mirror 19, and the third mirror 20, and the colorseparation optical system is arranged around the cross dichroic prism25. Further, the illumination optical system is designed to improve theutilization efficiency of the illumination light from the light sourceand to obtain uniform illumination light. The illumination opticalsystem is formed by the discharge lamp 1 operating as a light source,the lamp reflector 3, the lens 4, the lens 5, the polarizing conversionelement 6, the first lens array 7 that forms a optical integrator, themirror 8, and the second lens array 9. In addition, there is a lamppower supply 31 that provides power for the light source. In thisembodiment, the projection lens 27, the cross dichroic prism 25, thecolor separation optical system, the illumination optical system and thelamp power supply 31 are arranged from an upper part to a lower part inFIG. 1 in this order.

Further, optical parts of the color separation optical system and theillumination optical system are held within an optical case 200. Inaddition, the optical equipment includes a case 29, which is providedwith a first air intake opening 91, a second air intake opening 92, andan air exhaust opening 93. A ventilation unit 61 is provided for coolingthe first light valve 14, the second light valve 18, and the third lightvalve 21, respectively. A centrifugal fan is utilized as the ventilationunit 61 in this embodiment. Numeral 65 denotes a ventilation path tolead a cool air flow toward the lower portion of the optical case 200,and numeral 67 denotes a ventilation path for intake air flow. Numeral95 denotes a duct to lead intake air to the ventilation unit 61.

In FIG. 1, the air flow taken in from the air intake opening 91, flowsas shown by arrows W1 to W5 in the case 29 from operation of a fan forintake of air 63. Air is drawn into the ventilation path 67 from theintake side of the ventilation unit 61. The air flow that is used forcooling the first light valve 14, the second light valve 18, and thethird light 21 passes along the ventilation path 65 from the exhaustside of the ventilation unit 61, comes out into the upper part of thecase 29 and is discharged in the case 29.

Further, in this embodiment, as above-mentioned, the case 29 is providedwith a second air intake opening 92. The intake air is drawn in by thefan 62 and flow through the first lens array 7, the polarizingconversion element 6, lens 5, and the lamp power supply 31 and coolsthem.

In addition, the heat that is generated from the light source thatreaches a high temperature does not exert an influence on the structuralparts other than the light source itself. An exhaust fan 28 used forcooling the light source is arranged beside the discharge lamp 1 and thelamp reflector 3 so as not to influence structural parts other than thelight source by the high temperature that is generated by the lightsource, and a high velocity air flow 30 is exhausted to the outside ofthe case 29 of the projector through the exhaust opening 93. The lamppower supply 31 is arranged beside the discharge lamp 1. Simultaneously,the exhaust fan 28 draws out air from the case 29 for cooling the firstlight valve 14, the second light valve 18 and the third light valve 21.

In the following, details of the cooling provided in accordance withpresent invention will be explained with reference to FIG. 2 and FIG. 3.In FIG. 2 and FIG. 3 the ventilation unit 61 is arranged at the oppositeside of the position shown in FIG. 1. Accordingly, a cooling structureis shown in which the ventilation unit 61 is on the right side of theprojection lens 27 as you face it. However, it is possible for theventilation unit 61 to be arranged on the left side of projection lens27 as you face it.

FIG. 2 is a perspective view that shows an example of the ventilationpath. FIG. 3 is a perspective view that shows an example of the coolingstructure using the ventilation path that is indicated in FIG. 2. Theperspective views of FIG. 2 and FIG. 3 represents a view as seen fromthe X direction of FIG. 1.

As shown in FIG. 2, a first guide member 123, a second guide member 124,a third guide member 125, and a fourth guide member 126 are arrangedsuch that a cooling air flow is divided into a first air flow path 101and a second air flow path 102 by the first guide member 123.Consequently, the cooling air is divided into a first air flow, whichpasses through the first air flow path 101 to cool the second lightvalve 18, and a second air flow which passes through the second air flowpath 102 to cool the first light valve 14. Next, the second air flowpath 102 is divided into a third air flow path 103 and a fourth air flowpath 104 by the second guide member 124. Consequently, the cooling airis divided into a third air flow and a fourth air flow. The third airflow passes through the third air flow path 103 to cool the first lightvalve 14. The fourth air flow passes through the fourth air flow path104 to cool the third light valve 21.

Further, the first air flow path 101 is divided into a fifth air flowpath 105 and a sixth air flow path 106 by the fourth guide member 126.Consequently, the cooling air is divided into a fifth air flow and asixth air flow. The fifth air flow passes through the fifth air flowpath 105 and flows to the incoming light side of the second light valve18 to cool the incoming light side of the second light valve 18. Thesixth air flow passes through the fifth air flow path 106 and flows tothe outgoing light side of the second light valve 18 to cool theoutgoing light side of the second light valve 18.

Further, the second air flow path 102 is divided into a seventh air flowpath 107 and an eighth air flow path 108 by the second guide member 124.Consequently, the cooling air is divided into a seventh air flow and aneighth air flow. The seventh air flow passes through the seventh airflow path 107 and flows to the incoming light side of the first lightvalve 14 to cool the incoming light side of the first light valve 14.The eighth air flow passes through the eighth air flow path 108 andflows to the outgoing light side of the first light valve 14 to cool theoutgoing light side of the first light valve 14.

Further, the fourth air flow path 104 is divided into a ninth air flowpath 109 and a tenth air flow path 110 by the third guide member 125.Consequently, the cooling air is divided into a ninth air flow and atenth air flow. The ninth air flow passes through the ninth air flowpath 109 and flows to the incoming light side of the third light valve21 to cool the incoming light side of the third light valve 21. Thetenth air flow passes through the tenth air flow path 110 and flows tothe outgoing light side of the third light valve 21 to cool the outgoinglight side of the third light valve 21.

Next, the cooling structure for cooling the light valves will beexplained in detail with reference to FIG. 3. As shown in FIG. 3, thefifth air flow, that is one of the air flows for cooling with airflowing from the ventilation path 65, is ventilated to the incominglight side of the second light valve 18. Accordingly, the fifth air flowis ventilated to the side of the second incoming light side polarizingplate 82 and is used for cooling both the incoming light side of thesecond light valve 18 and the second incoming light side polarizingplate 82.

Further, the seventh air flow, that is ventilated from the ventilationpath 65, flows to the incoming light side of the first light valve 14.Accordingly, the seventh air flow is ventilated to the side of the firstincoming light side polarizing plate 81 and is used for cooling both theincoming light side of the first light valve 14 and the first incominglight side polarizing plate 81. The eighth air flow is ventilated to theoutgoing light side of the first light valve 14 and cools both theoutgoing light side of the first light valve 14 and the incoming lightside of the cross-dichroic prism 25.

Further, the ninth air flow, that is ventilated from the ventilationpath 65, flows to the incoming light side of the third light valve 21.Accordingly, the ninth air flow is ventilated to the side of the thirdincoming light side polarizing plate 83 and is used for cooling both theincoming light side of the third light valve 21 and the third incominglight side polarizing plate 83. The tenth air flow ventilated from theventilation path 65 flows to the outgoing light side of the third valve21 and the incoming light side of the cross dichroic prism 25.

One example of the structure that is used for cooling the first lightvalve 14, the second light valve 18 and the third light valve 21 hasbeen described. However, the air volume and air velocity can be easilyadjusted for each of the first to tenth air flows, if the position andthe shape of each of the first to fourth guide members 123, 124, 125,and 126 is arranged properly. For instance, in the case where thecalorific value of the outgoing light side of the second light valve 18and the outgoing light side of the first light valve 14 is large, eachguide member, such as guide members 123, 124, 125, may be arranged so asto carry a maximum amount of the ventilation volume and air velocity ofthe sixth air flow for cooling the second light valve 18 and the eighthair flow for cooling the first light valve 14.

Further, in the case where the calorific value of the third light valveis not large, the ventilation of the ninth air flow and the tenth airflow is throttled by the guide members. Therefore, the value of theincreasing temperature can be substantially equalized. Further, it iseasy to control the value of the increasing temperature on the incominglight side of each the first to third incoming light side polarizingplates 81, 82, and 83, if the velocity of each of the fifth, seventh andninth air flows is adjusted by the second to fourth guide members 124,125, and 126. As a result, the air velocity produced by ventilation unit61 can be used very efficiently.

As shown in FIG. 2 and FIG. 3, in accordance with this invention, sincethe ventilation path is formed by a plurality of divided flow paths,each of the first to the third light valves 14, 18, and 21 has their ownflow path such as flow paths 101, 102, 103, and 104. Therefore, thepresent invention is effective for achieving miniaturization and a thintype of optical equipment. Further, the present invention can provideoptical equipment that has a cooling system which operates with a highefficiency to cool a light valve arrangement having a large calorificvalue.

In addition, the present invention, which uses a centrifugal fan as theventilation unit 61, provides divided flow paths to obtain a smooth flowof the cooling air so as to reduce the pressure loss of the air flow tothe incoming and outgoing light side of each light valve. Accordingly, asufficient volume of air can be achieved. Further, the present inventioncan provide an efficient cooling system and cut down on the height ofthe optical equipment. The present invention can supply cooling air fromthe ventilation unit 61 to each the first to third light valves 14, 18,and 21 so as to equalize the increase in temperature of each of thefirst to third light valves 14, 18, and 21. Therefore, the presentinvention can adequately decrease the temperature of each of the firstto the third light valves 14, 18, and 21.

The present invention provides optical equipment having an efficientcooling system that can control the air volume and air flow velocityfreely. The present invention can adjust the air volume and air flowvelocity to the second light valve 18 and the third light valve 21 sothat their light absorption factors become large, and control the airvolume and air flow velocity to the first light valve 14 so that itslight absorption factor becomes small. Therefore, the present inventioncan adjust the air flow that passes through the flow path and provideoptical equipment with an efficient cooling system. Further, the presentinvention can control the incoming and outgoing right side of the firstto third valves 14, 18, and 21 so as to reduce the temperature of eachthe first to the third light valves 14, 18, and 21 to within apermissive range.

In the above-described embodiment, the air flow from the ventilationunit 61 is divided by the first to fourth guide members 123, 124, 125,and 126. A similar effect can be obtained if the structure is divided bydifferent pipes having a plurality of cross sections. In thisembodiment, because the first air intake opening 91 is arranged on theend of the case 29 and the exhaust opening 93 is arranged on the side ofthe case 29, the height of the optical equipment is reduced. Further,because an exhaust fan 28 is arranged beside the discharge lamp 1, theexhaust fan 28 cools the discharge lamp 1 easily.

Next, the position of the ventilation unit in the optical equipmentaccording to the present invention, are shown in FIG. 4 and FIG. 5, willbe described. FIG. 4 is a perspective view that shows an embodiment ofthe optical equipment according to the present invention. FIG. 5 is aperspective view that shows still another embodiment of the opticalequipment according to the present invention. In FIG. 4 and FIG. 5, eachelement that has the same function as described with reference to FIG. 1to FIG. 3 is identified by the same number. FIG. 4 and FIG. 5 areperspective views as seen from the bottom of the equipment.

In the above-mentioned embodiment shown in FIG. 1, the ventilation unit61 is stationed on the left side of the projection lens 27. Theventilation unit 61 is positioned in this embodiment at an angle of 90degrees relative to the ventilation unit 61 in FIG. 1. The ventilationunit 61 in FIG. 4 is positioned on the opposite side as compared to theventilation unit 61 in FIG. 5.

The ventilation unit 61 shown in FIG. 4 and FIG. 5 can producesubstantially the same effect as that of the above-mentioned embodiment.Accordingly, the air intake direction of the ventilation unit 61 isarranged at the side of the case 29, especially the upper side of thecase 29 shown in FIG. 1, and so the intake of the air can beaccomplished with little air flow resistance so as not to require spacefor an air flow path on the bottom side of the optical equipment. Thesame effect is provided furthermore whether the ventilation means is onthe right or left of the projection lens 27, as shown in FIG. 4 and FIG.5. When ventilation path 65 is located on the right or the left, such asfor the optics unit 200 shown in FIG. 4 or FIG. 5, it is possible toprovide a constitution that ventilates the first to the third lightvalves 14, 18, 21.

FIG. 6 is the sectional view that shows another example of the coolingarrangement that is used for optical equipment according to the presentinvention.

The cooling system according to the present invention can be applied inaddition to the three light valves 14, 18, 21 individually. That is, itis possible also to adapt it to cool a light valve by applying a largeamount of air to the center part of large calorific value of alarge-sized sheet 210 of a light valve as shown in FIG. 6 to decreasethe circumference.

In FIG. 6, the air flow through the ventilation path 65 from theventilation in unit 61 is divided and flows to the center of the lightvalve 210 as a first air flow (arrow 101A), and to the peripheral partof the light valve 210 as a second air flow (arrow 102A) and a third airflow (arrow 103A) so as to cool the large light valve 210. In this case,because the intake of the air by the ventilation unit 61 is producedfrom the side of the case 29, the optical equipment can reduce theintake air flow resistance, which is advantageous in thin type opticalequipment.

In the foregoing embodiment, the ventilation unit 61 is utilized as ameans to direct an air flow toward the light valve, however, thefollowing embodiment provides a ventilation unit 61 which draws in airto cause an air flow through the light valve. FIG. 7 is the sectionalview that shows another embodiment of the cooling structure that is usedfor optical equipment according to the present invention.

In FIG. 7, the ventilation unit 61 is positioned with the light valveson the exhaust side thereof, and the ventilation unit 61 causes air forcooling to be drawn in through the first to third light valves 14, 18,21. After the air, which flows through the ventilation path 65 and thesecond air flow path 103, cools the first light valve 14, the air isexhausted through the ventilation unit 61. After the air, which flowsthrough the first air flow path 101, cools the second light valve 18,the air is exhausted through the ventilation unit 61. Also, after theair, which flows through the fourth air flow path 104, cools the thirdlight valve 21, the air is exhausted by the ventilation unit 61 to theoutside of the case 29.

In the foregoing embodiment, the structure is such that the depth of thelight projector is larger than the width of the light projector.However, the present invention is not limited to that. In other words,the width of the light projector may be larger than the depth of theprojector.

FIG. 8 is a plan view that shows a still further embodiment of theoptical equipment according to the present invention. In FIG. 8, thelight 2, from the discharge lamp 1 that is used as a light source isdirected to a polarizing conversion element 6 by a lamp reflector 3 inthe form of a parabolic mirror reflector, via a lens 4 and lens 5, andthen is directed to a dichroic mirror 40 through a first lens array 7, amirror 8, and a second lens array 9. The dichroic mirror 40 reflects ared color light component 41 and passes the remaining light beam 42,including a green color light component and a blue color lightcomponent. The red color light component 41 is reflected by the mirror13 and directed to a first light valve 14. The green color lightcomponent 16 included in the light beam 42 is reflected by the seconddichroic mirror 15 and is directed to the second light valve 18. Theblue color light component 17 included in the light beam 42 is passed bythe second dichroic mirror 15, and the blue color light component 17 isdirected to the third light valve 21 through the second mirror 19 andthe third mirror 20.

A portion of the red light component supplied from the first light valve14, a portion of the green light component supplied from the secondlight valve 18, and a portion of the blue light component supplied fromthe third light valve 21 are combined by a cross dichroic prism 25. Thecombined outgoing light beam 26 from the cross-dichroic prism 25 isprojected on a screen (not shown) by a projection lens 27. In thisembodiment, the outgoing light from the discharge lamp 1 is bent to aU-shape and projected on the screen (not shown).

The heat that is generated from the light source and produces a hightemperature is prevented from exerting an influence on the structuralparts other than the light source. For this purpose, an exhaust fan 50used for cooling the light source is arranged beside the discharge lamp1 and the lamp reflector 3 so as to prevent the structural parts otherthan the light source from being influenced by the high temperature thatis produced by the light source, and a high velocity air flow 45 isexhausted to the outside of the case 44 of light projector. The lamppower supply 31 is arranged beside the discharge lamp 1.

In FIG. 8, the projection lens 27 and the cross-dichroic prism 25 arealigned from right to left. The color separation optical systemcomprises the first dichroic mirror 40, the second dichroic mirror 15,the first mirror 13, the second mirror 19, and the third mirror 20, thecolor separation optical system being arranged around the cross dichroicprism 25.

Further, the illumination optical system is designed to improve theutilization efficiency of the illumination light from the light sourceand to obtain uniform illumination light. The illumination opticalsystem is formed by the discharge lamp 1 operating as a light source,the lamp reflector 3, the lens 4, the lens 5, the polarizing conversionelement 6, the first lens array 7 that forms an optical integrator, themirror 8, and the second lens array 9. In addition, there is a lamppower supply 31 that provides power for the light source. In FIG. 8, theprojection lens 27, the cross dichroic prism 25, the color separationoptical system, the illumination optical system and the lamp power 31are arranged from the upper part to the lower part in this order.

In the embodiment shown by FIG. 8, the ventilation unit 61 is arrangedon the left side of the projection lens 27 similar to the embodiment ofFIG. 1, but it also may be arranged on the right side thereof. Theintake of the air by ventilation unit 61 is drawn in as shown by arrowW11, and is ventilated in the case as shown an arrow W12. Therefore,this optical equipment can be miniaturized, and the height of theequipment can be reduced. In FIG. 8, the exhaust fan 50 can be removedor moved to another place. The ventilation unit 61 may be stationedbetween the projection lens 27 and discharge lamp 1.

As explained above, in the optical equipment according to the presentinvention, the intake of cooling air is from a side face, and the intakeair opening and the exhaust an opening are arranged on different sidefaces. Therefore, the air flow resistance of the optical equipment canbe reduced and the cooling effect raised, while reducing height of theequipment. Further, because the ventilation path comprises a pluralityof divided air flow paths in accordance with this invention, each of thefirst to third light valves 14, 18, 21 have individual air flow paths101, 102, 103, 104, respectively. Therefore, this invention is usefulfor miniaturization of the equipment and provision of thin-typeequipment, and can provide optical equipment with a highly efficientcooling system.

Further, the present invention uses a centrifugal fan as the unit means61 and provides divided flow paths to obtain a smooth flow of coolingair so as to reduce the air pressure loss at the incoming and outgoinglight sides of each of the light valves. Accordingly, a sufficient airflow volume can be obtained. Further the present invention can providean efficient cooling system and cut down on the height of the opticalequipment. Accordingly, the present invention can reduce the height ofthe optical equipment and provide for miniaturization of the opticalequipment, while at the same time providing the optical equipment with ahigh efficiency cooling system. Further, the optical equipment can coola plurality of light valves to a substantially equal temperature.

1. A projection type display apparatus comprising: a housing having afirst side on which an air intake opening is arranged and a second sideon which an air exhaust opening is arranged; a light source forsupplying light; a light valve device which modulates the light outputfrom the light source; a first fan which draws air from the air intakeopening into the housing; a first ventilation path coupled with the airintake opening so as to lead air flow from the air intake opening towarda lower portion of the light valve; a second ventilation path formedfrom the lower portion of the light valve to an upper portion of thelight valve; and a second fan which draws out air flowing from thesecond ventilation path through the air exhaust opening to outside ofthe housing.